三维超新星（图）   

Supernovae—Now in 3-D!

Avatar may be breaking box office records here on Earth, but another 3-D event is creating a stir beyond our solar system. Astronomers at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, have used phenomena called light echoes to reconstruct in three dimensions the explosive death of a giant star whose light originally touched our world 330 years ago. Such echoes occur when the supernova's bright flash bounces off of dust clouds in various locations around the galaxy. Like strategically placed mirrors, the reflections can convey subtle details about these titanic explosions. In the case of this star, called Cassiopeia A, the 3-D reconstruction reveals that some parts of the blast traveled nearly 15 million kilometers per hour faster than others (green areas), giving Casiopeia A's demise a rather non-spherical appearance—something that can be seen here without the aid of special glasses.

三维电影《阿凡达》可能正在地球上创造票房纪录，但是另外一个三维事件正在太阳系之外引起轰动。马萨诸塞州剑桥市哈佛-史密森天体物理中心的天文学家们利用被称为“回光”的现象，重现了一颗巨型恒星爆炸死亡的三维图像。该恒星的光线是在330年前最初到达我们地球的。当超新星明亮的闪光通过星系周围不同之处的尘埃云团反射回来时，回光现象就产生了。就象处于关键位置的镜子，其映像可以表现出这些大型爆炸事件的细微之处。至于这颗被称为“仙后座A”的恒星，三维重现图像显示冲击波的某些部分比其他部分（绿色部分）穿行速度每小时快1,500万公里，在很大程度上使仙后座A的残骸呈现出非球形外观，这一点在地球上不用借助于特殊的望远设备就可以看得到。